We Protestants believe that God alone can forgive sin.

The Catholic Answers

And that is the Catholic teaching also. But the question concerns the way in which God has chosen to administer that forgiveness. We Catholics add that God can delegate His power if He wishes, just as the supreme authority in the state can delegate a judge to administer justice. Would you deny to God that power?

Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty